1. Field of the Disclosure
The present disclosure relates generally to an apparatus and method for controlling a security mode in a wireless communication system, and more particularly, to an apparatus and method for controlling a security mode such that a security configuration set in a user equipment (UE) is identical to a security configuration set in a network in a wireless communication system.
2. Description of the Related Art
In a radio communication system, a security process is vital to ensuring system reliability. For example, a security process includes an integrity process and a ciphering process in a radio communication system such as a universal mobile telecommunication system (UMTS), a code division multiple access (CDMA) mobile telecommunication system, a long-term evolution (LTE) mobile telecommunication system, and a long-term evolution-advanced (LTE-A) mobile telecommunication system.
The integrity process ensures no rogue network will be able to transmit unnecessary signaling messages to cause or intend to cause any undesired effect in an ongoing call.
The ciphering process ensures all signaling messages and data messages are ciphered over an air interface to inhibit a third party from eavesdropping on the signaling and data messages.
In a wireless communication system, a UE typically negotiates with a network to set security parameters such as encryption keys for use in encrypting (or ciphering) communications between the UE and each of network entities included in the network. The security parameters may be updated and/or changed to ensure secrecy of data transmitted/received between the UE and the network entities.
Specifically, a network transmits a security mode command (SMC) message including security parameters to a UE. After receiving the SMC message from the network, the UE sets or updates security parameters based on the security parameters included in the SMC message. Security parameters which have been previously set will be referred to herein as ‘old security parameters’, and security parameters which are newly set will be referred to herein as ‘new security parameters’.
The UE updates the security parameters which have been set in the UE to the new security parameters, and uses the new security parameters. The UE transmits an SMC complete message as a response message to the SMC message to the network before using the new security parameters. After receiving the SMC complete message from the UE, the network communicates with the UE using the new security parameters.
Even though the network transmits the SMC message to the UE, an out-of-service (OOS) situation may occur due to various reasons, and thus the UE is unable to receive the SMC message. In this case, the UE is also unable to transmit the SMC complete message as the response message to the SMC message to the network. Thus, the network detects that it is impossible to communicate with the UE using the new security parameters.
As such, the network performs a rollback process for the new security parameters to discard the new security parameters, and reuses the old security parameters.
If the UE is no longer in the OOS situation and receives the SMC message which the network has transmitted, the UE updates the new security parameters included in the SMC message and communicates with the network using the new security parameters.
In this case, the UE communicates with the network using the new security parameters and the network communicates with the UE using the old security parameters. Accordingly, a normal communication becomes impossible due to an incongruity between the security parameters used in the UE and the security parameters used in the network.
Accordingly, there is a need in the art for a method for controlling a security mode such that security parameters, i.e., a security configuration used in a UE corresponds to a security configuration used in a network.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.